Gate-geometry dependence of electrical characteristics of p-GaN gate HEMTs

Lee, Ethan S.; Joh, Jungwoo; Lee, Dong Seup; Alamo, J.A. del

doi:10.1063/5.0084123

Cited by 8 publications

(3 citation statements)

References 19 publications

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“…AlGaN/ GaN HEMTs operate in D-mode (depletion mode), which is a normally-on operation mode, as well as E-mode (enhancement mode), which is a normally-off operation mode. In recent years, numerous methods are being investigated, such as recessed gates [3], p-GaN gates [4,5], fluorine implantation [6], and cascade design [7] to achieve normally-off operation of GaN HEMTs. Depending on the application, normally-on or normally-off GaN HEMTs are used.…”

Section: Introductionmentioning

confidence: 99%

Exploring the impact of AlGaN barrier thickness and temperature on normally-on GaN HEMT performance

Hidayat,

Usman

2024

Eng. Res. Express

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Theoretical studies are conducted on varying barrier thicknesses in GaN/AlGaN HEMTs, as well as the effect of temperature fluctuation on device functionality. Structures A, B, C, D and E are designed each with barrier thickness 16 nm, 19 nm, 22 nm, 25 nm, and 28 nm respectively. A theoretical model is explained that helps to understand the impacts of barrier thickness variation on surface barrier height, strain relaxation and 2DEG concentration. The concept is further expanded to include the GaN HEMT's drain and transfer properties. Investigations are also done on how different thermal impacts affect the functionality of the device. We contemplate alloy disorder, interfaceroughness (IFR) as well as polar-optical phonon scattering. At elevated temperatures, the polar-optical phonon dispersion is the predominant process. Yet, at lower temperatures, the IFR and alloy disorder dispersion both satisfactorily account for the reported mobilities.

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Section: Introductionmentioning

confidence: 99%

Exploring the impact of AlGaN barrier thickness and temperature on normally-on GaN HEMT performance

Hidayat,

Usman

2024

Eng. Res. Express

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“…[22,23] The addition of a p-GaN layer to the AlGaN/GaN changes the resulting p-GaN/AlGaN/GaN HEMT (enhancement-mode) from normally-on to normally-off through band bending and suppression of 2-DEG at zero-bias, which leads to low dark current. [31][32][33][34][35] In previously reported enhancementmode p-GaN/AlGaN/GaN photodetectors, the p-GaN acted as the gate by the means of photo induced carriers. However, there are only a very few studies on the utilization of p-GaN/ AlGaN/GaN structure, and most of them focused on phototransistor mode of operation, where the area of the p-GaN optical gate is limited by the transistor geometry.…”

Section: Introductionmentioning

confidence: 99%

“…However, there are only a very few studies on the utilization of p-GaN/ AlGaN/GaN structure, and most of them focused on phototransistor mode of operation, where the area of the p-GaN optical gate is limited by the transistor geometry. [35][36][37] A widened p-GaN region on the photodetector would broadly and effectively suppress the 2-DEG, which could help in enhancing the photosensitivity through lowering the dark current. Moreover, the detailed operation mechanism and the effect of electrode transmittance on the photodetector performance still need to be explored further.…”

Section: Introductionmentioning

confidence: 99%

Highly Sensitive Ultraviolet Photodetector Based on an AlGaN/GaN HEMT with Graphene‐On‐p‐GaN Mesa Structure

Pandit

Jang

Jeong

et al. 2023

Adv Materials Inter

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The advantageous role of 2D electron gas presence at the AlGaN/GaN interface attracts huge interest in the field of GaN‐based ultraviolet photodetector technology. However, the presence of high dark current deteriorates the photodetector performance by diminishing several figures of merit. In this work, enhanced figures of merit are demonstrated by employing interdigitated p‐GaN finger structure on the top of the AlGaN/GaN heterostructure. The commonly present high dark current in p‐GaN/AlGaN/GaN planar photodetector is largely reduced (from ≈µA to few pA) by etching the p‐GaN, excluding the electrode region. Furthermore, by using a graphene transparent electrode along with the p‐GaN interdigitated fingers on AlGaN/GaN heterostructure, ultraviolet photodetectors with superior sensitivity (3.55 × 106) and ultrahigh detectivity (1.91 × 1014 cm Hz1/2 W−1) are realized at 360 nm. A comparison of graphene/p‐GaN and Ni/Au/p‐GaN interdigitated fingers and planar p‐GaN (with interdigitated graphene contacts) all on AlGaN/GaN heterostructure allows to understand the dominant roles of electrode transparency and the heterojunction structure. The simple and high electron mobility transistor‐compatible fabrication process of UV detectors provides a unique application in the field of UV sensing technology.

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Analysis and modeling of the influence of gate leakage current on threshold voltage and subthreshold swing in p-GaN gate AlGaN/GaN high electron mobility transistors

Liu,

Wang,

Zhang

et al. 2024

Journal of Applied Physics

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In this paper, the p-GaN gate AlGaN/GaN high electron mobility transistors (HEMTs) with varying combinations of gate metal work function and gate geometry are fabricated and investigate the influence of gate leakage current (IGS) on the threshold voltage (VTH) and subthreshold swing (SS). The unique dependence of VTH and SS on gate geometry for different metals is observed, which is different from traditional field-effect transistors. A novel hybrid physics model, consisting of the traditional capacitance divider model and hole injection model, is proposed to explain this phenomenon, and the results exhibit an excellent agreement with the experimental data. The holes traverse the gate/p-GaN Schottky barrier by thermal emission or tunneling and inject into the p-GaN layer, generating the IGS. Expanding upon the traditional capacitance divider model, a portion of the injected holes accumulate at the p-GaN/AlGaN interface and induce the corresponding electrons at the AlGaN/GaN heterojunction, which promotes channel conduction. Hence, the transfer curves display the correlation between IGS and VTH as well as SS. The results show that high IGS can alleviate the instability of VTH caused by the lithographic overlay error, and simultaneously optimize SS. This work offers a novel perspective for examining the turn-on mechanism of p-GaN HEMTs, thereby contributing to device design.

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Gate-geometry dependence of electrical characteristics of p-GaN gate HEMTs

Cited by 8 publications

References 19 publications

Exploring the impact of AlGaN barrier thickness and temperature on normally-on GaN HEMT performance

Exploring the impact of AlGaN barrier thickness and temperature on normally-on GaN HEMT performance

Highly Sensitive Ultraviolet Photodetector Based on an AlGaN/GaN HEMT with Graphene‐On‐p‐GaN Mesa Structure

Analysis and modeling of the influence of gate leakage current on threshold voltage and subthreshold swing in p-GaN gate AlGaN/GaN high electron mobility transistors

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